The present invention is directed to compositions of matter which are useful as additives for fuels such as gasoline utilized in spark-ignition engines.
With the advent of more sophisticated internal combustion engines and environmental requirements, the necessity for providing suitable fuels such as gasoline which contain additives has become increasingly important. It is well known that the hydrocarbon fuels such as gasoline which are used in these internal combustion engines contain numerous deposit-forming substances which, after a period of time, will inhibit the efficiency of the engine. The formation of deposits on and around areas of the engine which are contacted by the fuel will tend to adversely affect the operation of the engine and the vehicle in which the engine is situated. Some specific areas of the engine upon which the deposits are formed will include carburetor ports, the throttle, engine intake valves, the combustion chamber, etc. For example, clean valve intake systems and combustion surfaces are of primary importance, in order to reduce emissions, give improved gas mileage as well as improving the performance of the engine. Another important area which is vital to the performance of the automobile is the port fuel injectors. Any deposits which collect in the needle valve area can partially or totally block the flow of gas, thus resulting in poor performance, increased emissions, smoke and starting problems. Likewise, deposits on the carburetor throttle body and venturies increase the fuel-to-air ratio of the gas mixture to the combustion chamber thereby increasing the amount of unburned hydrocarbon and carbon monoxide which is discharged from the chamber. The high fuel to air ratio also reduces the gas mileage which is obtained. As was previously stated, the engine intake valves should be maintained in a clean state inasmuch as deposits on the valves, when they amount to a sufficiently heavy coating, will restrict the gas mixture flow into the combustion chamber. The restriction of the gas flow will in effect starve the engine of air and fuel and thus will result in a loss of power. The deposits on the valves will also increase the probability of valve failure due to burning, sticking, and improper valve seating.
Another problem with utilizing gasoline as a fuel is that gasoline may contain a certain amount of water as well as oxygen. The combination of oxygen, water and fuel in contact with ferrous metals which are utilized in many parts of the engine will result in the formation of corrosion products which interferes with the operation of the vehicle's fuel system and engine parts. The corrosion of the engine parts such as the fuel storage tank, fuel lines and injectors will interfere with the vehicle's operation thus resulting in a shorter engine life as well as the efficiency of the engine.
In addition to the problems attendant to the formation of deleterious deposits in the engine itself, the question of emissions from the exhaust system of the automobiles or trucks has also become a major problem. Major changes in the formulation of gasoline in order to reduce these noxious emissions are being proposed. These formulations will result in extremely clean fuels with low conductivity and will also afford fuels with lower vapor pressure. The clean, low vapor pressure fuels, especially gasoline, may become a safety hazard at the refinery, terminal loading racks or even at gasoline stations when the gasoline is pumped into the fuel tank of an automobile or truck. This is due in part to the fact that gasoline builds up static caused by the rapid loading procedures which are now in effect. Inasmuch as the high vapor pressure of present gasolines leads to displacement of oxygen, resulting in vapors that are too rich to burn, the chance of fire or explosion is diminished since the corona discharge of static at the loading places is quenched and dissipated. However, the new low vapor pressure gasolines will not have a sufficient amount of vapor release to displace oxygen resulting in a more combustible mixture in the vapor space over the liquid fuel during the loading operation. Subsequent static buildup with release as a corona discharge then becomes a major safety problem. In order to overcome this problem, fuel additives which possess a conductivity characteristic will be required which bleed away the static charge buildup on the tank walls to grounding wires which will dissipate the electrical energy to the ground.
In view of the problems which are attendant to present and future fuels such as gasoline, it is necessary that an additive be utilized with the gasoline which possesses the desirable properties of being able to control deposits on the internal parts of the engine, act as a corrosion inhibitor, possess surfactant, and to have antistatic and conductivity properties. As will be shown in greater detail, the conductive fuel detergent composition or additive of the present invention will fulfill these requirements.
Several United States Patents address the problems which have been previously set forth with regard to efficient operation of the gasoline engine. For example, U.S. Pat. No. 4,600,409 describes a fuel additive comprising a quaternized polyoxyalkylene polyamine or polyether polyamine which is utilized in fuel compositions containing a major amount of a liquid hydrocarbon fuel boiling in the gasoline range. The additive is said to consist of three parts, the first being the polyether or polyoxyalkylene moiety which may or may not be capped by a hydrocarbo moiety. The polyether moiety is bound to a second moiety, through a connecting group or linkage to the nitrogen atom of the third moiety, the amine, which is quaternized by an appropriate alkyl halide. Another U.S. Pat. No. 3,468,640 also describes an additive or gasoline comprising a quaternary ammonium base which is soluble in oil and gasoline. In addition, U.S. Pat. No. 4,132,657 describes a class of amphoteric surfactants which are utilized in the treatment of metal surfaces. These surfactants comprise ethoxylated amines which are quaternized and at least partially phosphated. These surfactants are utilized to treat metal surfaces to improve the lubricating, rust and corrosive inhibiting properties of the surfaces. U.S. Pat. Nos. 4,564,372 and 4,581,151 both disclosed quarternized polyoxyalkylene polyamines or polyetheramines of various compositions which may be used as fuel additives. These are similar in nature to the compounds disclosed in previously discussed U.S. Pat. No. 4,600,409.
The patentees of U.S. Pat. No. 4,388,200 have described compositions touted as dispersants and/or detergents for lubricating oils which resemble those of the current application, although it is noteworthy that the patentees use their materials for totally different purposes than does applicant here, and applicant utilizes quite different properties of the compositions (viz., conductivity) than do the patentees (viz., detergency). It also is noteworthy that the patentees require that the quaternary ammonium function be incorporated in a pyridine ring, quite different and more restrictive than is the case with the instant invention.